Genus Helicotylenchus 
Steiner, 1945
 syn.: Rotylenchoides Whitehead, 1958 
   Zimmermannia  Shamsi, 1973
Photo Gallery-Homestead Nat'l Monument
Photo Gallery- Haughton Crater
Photo Gallery- Barta Brothers Ranch

Female: Body vermiform, spiral to straight. Labial region continuous to slightly offset, rounded or anteriorly flattened, generally annulated but never longitudinally striated; anterior lip annulus generally not divided into sectors, with elongate amphid spertures (SEM). Rarely faint or marked lip sectors are present. Lateral field with four lines. Phasmids small, near anus; cephalids and caudalid present. Tail 1 to 2 1/2 body diameters long, typically more curved dorsally, with or without a terminal ventral process, sometimes rounded. Stylet and labial framework average-sized. DGO from 6 to 16 um from stylet base. Median bulb rounded with average-sized valve. Glands overlap intestine dorsally and ventrally, all three glands of about the same length. Two genital branches, the posterior one sometimes degenerated or reduced to a PUS. Epiptygma present, inconspicuous. Male: Slight secondary sexual dimorphism seen in smaller anterior end. Caudal alae enveloping tail end.

Species found:      at:
H. digonicus Konza Prairie, 9 Mile Prairie, Haughton Crater 
H. labiodiscinus Konza Prairie, Homestead
H. leiocephalus 9-Mile Prairie
H. platyurus Konza Prairie, 9 Mile Prairie, Homestead
H. pseudorobustus Konza Prairie, 9 Mile Prairie

Species List  from Ebsary, 1991